Marimba / Engineering / Katie

To create the keys I chose to use red oak because hardness is directly proportional to tone, and red oak has a very high Janka hardness rating, giving it a good tone for marimbas. By testing different length samples of the material, I was able to derive an algorithm that relates key length to pitch, which I used to determine the key lengths for the standard 5 octaves of a marimba. By supporting each key in a manner that mimicked the actual playing position, I was able to test and tune each key before assembling the final instrument.
The keys are suspended on a cord running through 180 eye hooks, and tensioned at the end by wrapping around a sturdier eye hook such that all of the keys are suspended 1/4" above the frame.
The resonators are constructed from PVC pipe. The proper length for each resonator was determined by using the closed-ended-tube equation for the first fundamental frequency of each key, in the theory that the resonator would amplify the note produced by the key. The resonators that are longer than the height of the instrument curve around through the use of plumbing fixtures because the straightness of a pipe does not affect its resonant qualities. The resonators are all suspended below the keys on aluminum rails.
This instrument is completely playable and meets my standards as a former percussionist.

Engineering: Marimba

5 Octave Marimba

Comments: 0